The trend sensors went off for the first time on the weekend of April 6, when Real Salt Lake's Álvaro Saborío had a penalty attempt saved by the Colorado Rapids' Clint Irwin and the Chicago Fire's Chris Rolfe fired his penalty wide left of the goal against the New York Red Bulls the next day.
A week later, FC Dallas forward Kenny Cooper had a penalty saved by the LA Galaxy's Carlo Cudicini, and Landon Donovan had his shot snuffed out by FCD's Raúl Fernández just eight minutes later.
Vancouver's Camilo Sanvezzo scored on a penalty against Real Salt Lake's Nick Rimando and Colorado's Deshorn Brown beat Chivas USA's Dan Kennedy from the spot on April 13, but Chivas USA's Edgar Mejía was stopped from the spot by Rimando a week later, and the sensors lit up again.
And then just last week, the Crew's Federico Higuaín was stoned by New York goalkeeper Luis Robles, en route to a Red Bulls win in Columbus. And Donovan, who's made so many clutch PKs in his career for both LA and the US national team, had another one saved the next day, this time by Houston's Tally Hall.
The sensors kicked into overload. So, we called upon the Elias Sports Bureau to see what was up.
WATCH: Higuain stopped by Robles
Here's what we got.
In the history of MLS, penalties have been converted at a 76.6 percent rate (748 of 977 penalties have resulted in goals). This season, penalties are being converted at a 55 percent rate (11 of 20 have been converted). It's a small sample size, but it's a trend.
So as we head into this week's games – which begin with six matches on Wednesday night – we're left to wonder: Is failing to convert penalties contagious?
Donovan, for one, might agree. After he missed his second PK attempt in just three tries this season last weekend against Houston, he suggested that the next Galaxy penalty will be taken by someone else, and head coach Bruce Arena agreed.
"It’s tough for Landon," Montreal Impact midfielder Patrice Bernier told MLSsoccer.com. "He’s missed two, and after that, all you can do is evacuate the tension. You must not think about it again. The more you replay the sequence in your head, the more chances that, the next time he gets a chance, there’ll be doubts in his head.
“All you need is one image of a missed attempt in your mind for you to hesitate when you strike the ball."
Bernier has made the one and only penalty he has taken this year, and has made seven straight, tying him with the Philadelphia Union's Conor Casey for the longest active streak of converted penalties. The Union have yet to take a penalty in 2013.
WATCH: Rolfe misses wide left
"I've seen some of the highlights of the saves and misses," Casey told MLSsoccer.com. "And, yeah, to hear those numbers is a bit alarming, but I'll just try to do my thing."
Casey's "thing" is a one-step run to the ball, maybe a slight peek to see if the keeper is moving, and a firm shot. He says he's got no issue with those who stutter-step like Higuain and Cooper, and insists, "you have to do what works for you."
Casey is 10 for 12 for his career, but may have to fight teammate Sébastien Le Toux for the ball (if they're both on the field) when the Union get their first PK of the season. Le Toux is perfect on the seven penalties he has taken in his MLS career.
Among those who've made five or more penalties in MLS regular-season games, only 10 have never missed: Jovan Kirovski (9 for 9), Bernier, Le Toux and Jorge Rodríguez (7 for 7), Ross Paule and Eric Wynalda (6 for 6), Cate, Damian, Brad Evans and Andrés Mendoza (5 for 5).
In other words, the guys who've made the most penalties in MLS history have had to bounce back from a miss or two along the way. Consider that Jaime Moreno made 20 more regular-season penalties (52) than the No. 2 all-time PK-converter in MLS history, Donovan. Moreno has also failed more times (8) than anyone, though Mamadou Diallo (7 for 12) would have likely shattered that record had he taken more in his career.
Moreno's confidence to step up to the spot was certainly bolstered by the 20 consecutive penalties he converted between April 3, 2005 and Aug. 30, 2008. When that run ended, with Moreno shooting wide left of Jon Conway's goal in the 81st minute of a 0-0 tie between D.C. United and the New York Red Bulls, Moreno gave up the spot to Christian Gómez the next time United were awarded a penalty.
WATCH: Cooper stopped again
Gómez converted, but Moreno returned to taking D.C.'s penalties and made the last four spot kicks of his MLS career.
Moreno did not allow one miss to turn into a trend. Will Donovan allow back-to-back misses to creep into his psyche?
"It depends on the individual, but for me, if I miss one or two, it's disappointing, but I'm still confident that I will score on the next one," said Toronto FC's Robert Earnshaw, who has converted both of his PK attempts this season. "It's not something that I will really get down about. If your technique is good, you are going to have a good chance at scoring. Sometimes you just have give a ‘keeper credit for a great save.
“Overall, I think you just have to be confident. I'm a confident guy, so if I miss one, then I'm on to the next one and I definitely want to take the next one."
Trend sensors be damned.